This invention relates to an illuminated seat belt buckle.
Ordinarily, a seat belt with which a vehicle, such as an automotive vehicle, is equipped is fastened in place to restrain the body of a passenger by inserting a tongue, through which the belt passes, into a buckle. A problem encountered is that it is not easy to find the receptacle portion of the buckle into which the tongue is to be inserted in an unlighted vehicle at night. For this reason, various proposals have been made in which an illuminating device is incorporated within the buckle to illuminate the tongue receptacle so that it can be seen in the dark.
For example, the arrangements disclosed in Japanese Patent Application Laid-Open (KOPKAI) No. 48-49126 and Japanese Patent Publication (KOKOKU) No. 55-30367, as well as the arrangements disclosed in Japanese Utility Model Application Laid-Open (KOKAI) No. 61-3155, Japanese Utility Model Application Laid-Open (KOKAI) No. 61-36469 and Japanese Utility Model Publication No. 63-42809, all have a configuration in which light source is incorporated in the mechanism of the buckle or in the illuminated portion itself.
In the disclosure of Japanese Patent Publication (KOKOKU) No. 55-30366, an arrangement is proposed in which an optical fiber is passed between a support plate and cover of the buckle mechanism, and the tip of the optical fiber is directed toward the tongue receptacle opening. In the buckle of Japanese Utility Model Publication (KOKOKU) No. 63-42807, a light source is provided on the rear portion of a cover, and the space within the buckle mechanism is used as an optical path to illuminate the edge of the tongue receptacle opening and a release button. Further, in the disclosure of Japanese Utility Model Publication (KOKOKU) No. 57-22803, an arrangement is disclosed in which a light-emitting diode serving as a light source is attached to the leading end of a case half to directly illuminate a member at the tongue receptacle opening.
In these examples of the prior art, in which the light source is incorporated in the buckle mechanism or the illuminated portion itself, a lamp, an LED or the like serving as the light source is arranged as close as possible to the illuminated portion in order to provide a sufficient amount of light with little power consumption. However, incorporating the light source in the buckle mechanism places a limitation upon the design of the lighting device and often makes it necessary to modify the buckle mechanism. It is difficult to provide a light source in a buckle having a conventional mechanism.
In known arrangements wherein the illuminating device is incorporated in the buckle mechanism in the space between cover and the mechanism, any influence upon the design of the buckle mechanism can be avoided, but the optical path is not as favorable and hence a sufficient amount of light cannot be introduced to the illuminated portion to illuminate it with uniform brightness.